With the recent widespread use of a writable drive for a computer specific CD-R (CD recordable)/CD-RW (CD rewritable), it has become possible to easily prepare a disk intended for home use. This permits preparation of a traditionally inconceivable multisession disk that has plural sessions with music or some other data recorded in each of them; hence, there is a demand for a multisession compatible disk player capable of playing back all pieces of music data recorded in the plural sessions.
FIG. 1 is a block diagram to depict the configuration of a conventional multisession compatible disk player. In FIG. 1, reference numeral 1 denotes a disk to be played back, and 1a denotes a recording session.
The recording session 1a is composed of first, second, . . . , and last sessions, each consisting of a lead-in area, a program area and a lead-out area. And contents information recorded in the lead-in area contains identification information about the recording format of the disk 1. In the first session there are recorded, as the identification information, session format information indicating whether the disk 1 is multisession or not, and disk format information indicating that the disk 1 is a read-only disk. In each of the first and subsequent sessions there are recorded the current session data format indicating that the current session has recorded therein music data or some other data, for example, ROM data for CD-ROM use, information about the next session contents information starting position, and so forth.
The disk 1, which has plural sessions, each consisting of the lead-in, program and lead-out areas as shown in FIG. 1, is a multisession compatible disk, whereas the disk 1 having one session is a single session disk.
Reference numeral 2 denotes a signal readout portion for reading out of the disk 1 a signal containing contents information; 3 denotes a signal processing portion that decodes the signal read out by the signal readout portion 2 and converts the decoded signal to data processable in the subsequent step; and 4 denotes a microprocessor that performs various processing, makes various decisions and controls the playback of the disk based on the signal processed by the signal processing portion 3.
In the microprocessor 4, reference numeral 5 denotes an identification information processing portion that identifies each piece of identification information contained in the contents information decoded by the signal processing portion 3; 6 denotes a multisession decision portion that decides whether the disk 1 is multisession or not based on session format information in the identification information identified by the identification information processing portion 5 which is recorded in the lead-in area of the first session on the disk; 7 denotes a disk type decision portion that decides the type of the disk 1 based on the result of decision by the multisession decision portion 6; 8 denotes a contents readout processing decision portion that decides the method for contents readout processing; and 9 denotes a control portion that controls the playback method based on the result of decision by the disk type decision portion 7 and controls the readout of contents information for each session based on the result of decision by the contents readout processing decision portion 8.
Next, the operation of the prior art example will be described below.
FIG. 2 is a flowchart to show the procedure for disk decision processing in the conventional multisession compatible disk player. In step ST11 the operation for playing back the disk 1 begins with reading out contents information in the first session by the signal readout portion 2, followed by decoding the read-out contents information by the signal processing portion 3 and then by identifying each piece of identification information contained in the decoded contents information by the identification information processing portion 5.
In step ST12 the multisession decision portion 6 decides whether the disk 1 has plural sessions based on the session format information in the identification information identified by the identification information processing portion 5 which is recorded in the lead-in area of the first session on the disk.
When it is decided by the plural session decision portion 6 in step ST12 that the disk has only one session, the procedure goes to step ST13, in which the disk type decision portion 7 decides that the disk 1 is a single session disk. When it is decided instep ST12 that the disk has plural sessions, the disk type decision portion decides in step ST14 that the disk 1 is a multisession disk.
In step ST15 the disk type decision portion 7 finishes the processing for deciding the type of the disk 1, and the control portion effects control for playing back the single or plural sessions according to the result of decision by the disk type decision portion.
FIG. 3 is a flowchart to show the contents information readout procedure in the conventional multisession compatible disk player. Steps ST11 to ST14 are the same as those ST11 to ST14 in FIG. 2.
When it is decided by the disk type decision portion 7 in step ST13 that the disk 1 is a single session disk, the contents readout processing decision portion 8 terminates the contents information readout processing since the disk has no contents information of the subsequent sessions, and the control portion 9 controls the signal readout portion 2 via the signal processing portion 3 to start the playback of the program area on the disk 1.
On the other hand, when it is decided by the disk type decision portion 7 in step ST14 that the disk 1 is a multisession disk, the procedure goes to step ST16, in which the contents readout processing decision portion 8 obtains information about the contents information starting position from the identification processing portion 5 and sends the information to the control portion 9, which, in turn, controls the signal readout portion 2 via the signal processing portion 3 to move to the next session contents position to read out contents information about the next session. During the movement of the signal readout portion 2 to the position where to start the readout of the contents information, the signal processing portion 3 sends information about an error between the current and target positions of the signal readout portion to the control portion 9; based on the error information sent thereto the control portion 9 controls the movement of the signal readout portion. And, as is the case with the first session contents information readout processing in step ST11, the signal processing portion 3 decodes the contents information and the identification information processing portion 5 identifies each piece of the identification information contained in the decoded contents information.
In the case where based on the information about the position of starting the next session contents information identified by the identification information processing portion 5 the contents readout processing decision portion 8 decides in step ST17 that the current session is followed by the next session, steps ST16 and ST17 are repeated until the current session is no longer followed by the next session. When the identification information processing portion 5 does not identify the information about the next session contents information starting position and consequently the contents readout processing decision portion 8 decides in step ST17 that the current session is not followed by the next session, the procedure goes to step ST18, in which the contents readout processing decision portion 8 terminates the contents information readout processing and the control portion 9 and causes the control portion 9 to start the playback of the program area on the disk 1.
Because of its configuration described above, the conventional multisession compatible disk player cannot distinguish between the multisession disk and a disk marketed under the name of an enhanced music CD, which has sessions of recording formats so specified as to record music data in the first session and some other data in the second session with no distinction from the single session disk—this gives rise to a problem that the conventional disk player inevitably plays back the data recorded in the second session as well as the data recorded in the first session as in the case of playing back the multisession disk.
Further, in the case of the multisession disk, since the data type indicating whether the recorded data music data or some other data is recorded in the contents information about individual sessions, it is impossible to decide which type of data is recorded in which session until contents information about all the sessions involved is read out; furthermore, in the case of the enhanced music CD having sessions of specified recording formats, too, it is necessary to read out the contents information about the second session, raising a problem of a delay in the start of playback.
The present invention is intended to solve such problems as mentioned above and has for its object to provide a multisession compatible disk player that based on first session contents information read out at playback time, decides that the disk to be played back is the enhanced music CD, in particular, and plays it back in the same manner as in the case of the single session disk.
Another object of the present invention is to provide a multisession compatible disk player that, in the case of the disk being decided as the enhanced music CD based on the result of decision, does not read out the second session contents information but reads out the first session contents information alone as in the case of an ordinary single session disk, there by starting the playback within about the same time as that for the single session disk.